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OMAP2+: hwmod: allow board files to prevent devices from being reset upon init

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Some boards can't tolerate IP blocks being reset when they are initialized.
Michael Büsch cites a case with the Nokia N810:

    http://www.spinics.net/lists/linux-omap/msg47277.html

To allow such boards to continue working normally, allow board file
maintainers to mark IP blocks to prevent them from being reset upon
init.  This is done via a hwmod function, omap_hwmod_no_setup_reset().

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Michael Buesch <mb@bu3sch.de>
This commit is contained in:
Paul Walmsley 2011-03-10 03:50:07 -07:00
parent dd9c1549ed
commit 43b0164335
2 changed files with 28 additions and 0 deletions
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26
arch/arm/mach-omap2/omap_hwmod.c
View File

@ -2218,3 +2218,29 @@ u32 omap_hwmod_get_context_loss_count(struct omap_hwmod *oh)
return ret;
}
/**
* omap_hwmod_no_setup_reset - prevent a hwmod from being reset upon setup
* @oh: struct omap_hwmod *
*
* Prevent the hwmod @oh from being reset during the setup process.
* Intended for use by board-*.c files on boards with devices that
* cannot tolerate being reset. Must be called before the hwmod has
* been set up. Returns 0 upon success or negative error code upon
* failure.
*/
int omap_hwmod_no_setup_reset(struct omap_hwmod *oh)
{
if (!oh)
return -EINVAL;
if (oh->_state != _HWMOD_STATE_REGISTERED) {
pr_err("omap_hwmod: %s: cannot prevent setup reset; in wrong state\n",
oh->name);
return -EINVAL;
}
oh->flags |= HWMOD_INIT_NO_RESET;
return 0;
}

2
arch/arm/plat-omap/include/plat/omap_hwmod.h
View File

@ -589,6 +589,8 @@ int omap_hwmod_for_each_by_class(const char *classname,
int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state);
u32 omap_hwmod_get_context_loss_count(struct omap_hwmod *oh);
int omap_hwmod_no_setup_reset(struct omap_hwmod *oh);
/*
* Chip variant-specific hwmod init routines - XXX should be converted
* to use initcalls once the initial boot ordering is straightened out